Multi-scale performance simulation and effect analysis for hydraulic concrete submitted to leaching and frost

The long-term behavior and safety performance of hydraulic concrete structures are influenced by chemo-mechanical deterioration due to leaching and frost. The single-scale experimental investigations on the certain deterioration phenomenon of concrete structure submitted to leaching or frost have been performed. In this work, the multi-scale numerical simulation approach is introduced to analyze the deterioration phenomena due to leaching or/and frost in hydraulic concrete and the structural responses to the above deterioration phenomena. The three-dimensional (3D) multi-scale modeling and homogenization methods of hydraulic concrete submitted to leaching or/and frost are developed. The effect analysis of leaching or/and frost on the mechanical properties of hydraulic concrete is implemented. First, according to the multi-scale and multi-phase characteristics of hydraulic concrete as composite material, the scale separation standard of hydraulic concrete is given. The hydration model and random aggregate model are introduced to reconstruct the representative volume element model of hydraulic concrete with different scales, namely micro-scale (cement paste), meso-scale (mortar), macro-scale (concrete). The numerical homogenization method is presented to determine the mechanical properties of the hydraulic concrete. Second, the methods are developed to implement the 3D multi-scale simulation for random leaching process and thermo-mechanical coupling frost damage process of hydraulic concrete. Regarding seepage leaching as the leading role, a numerical method investigating the combined effect of leaching and frost on the mechanical properties of hydraulic concrete is proposed. Finally, the water-saturated hydraulic concrete is taken as an example. The deterioration phenomena due to leaching or/and frost in selected concrete are analyzed. The structural responses to the above deterioration phenomena are identified. It is indicated that the proposed multi-scale progressive analysis approach can capture the potential deterioration phenomena of hydraulic concrete. The variation mechanism of concrete structural behavior can be given a deeper insight. It can be seen that the nonlinear superimposed effect of leaching and frost can easily cause serious damage of water-saturated hydraulic concrete.